David Element's Wildlife Web Page Beetles 2

David Element

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____________________ Beetles 2 - Stag-Beetles 1

STAG-BEETLE Lucanus cervus (m)

This remarkable insect is the largest European beetle and a member of the family Lucanidae. Only the males possess the enormous mandibles - females have much smaller jaws which may actually produce a more effective bite than those of the males. See Beetles 11 for further photographs of members of this family.

Either sex can inflict a painful nip if injudiciously handled but without this interference they pose no threat to humans. Medium sized males are often the most active combatants and their jaws probably have more purchase than those of very large males. However, the threatening appearance of a very big male is usually sufficient to deter attack from smaller rivals. Larger male Stag-beetles are quite capable of killing their rivals and can occasionally cut an opponent in half! Many older beetles lack their full set of limbs or possess dents as a consequence of fighting.

Stag-beetle larvae live in decaying wood and they may take over five years to achieve maturity. The adults emerge from late May to August in Britain and there is evidence to suggest earlier emergence dates in respose to a warmer climate. The main flight period is normally between 9:00 and 10:00PM.

Over-zealous forestry practices (e.g. the removal of dead wood, the planting of inappropriate tree species) have caused the population of this beetle to fall into serious decline throughout Europe and it is gratifying to note that it has at long last received some legal protection in Britain. The Great Storm of October 1987 may have been beneficial in areas where dead trees were allowed to lie in situ although there have been too few generations since this event to confirm this. Suburban gardens remain a very valuable habitat, particularly if there is dead wood at or below ground level. At Kew Gardens there is a specially dedicated rotting log pile for this and other xylophagous (wood-eating) insects.

The quality of nutrition received during larval development influences the size of the adult beetles and there is a huge degree of variation with the largest recorded male achieving a length of 77mm. This specimen was captured during the 19th Century and it is held in the collection of the Natural History Museum in London.

The individual shown in most of the photographs above was 70mm long with very well developed mandibles. He was photographed during the millennial summer which proved to be a good season for these beetles in their London stronghold.

RECOMMENDED READING

'The Bulletin of the Amateur Entomologists' Society' Volume 62 Number 451, December 2003 contains some highly informative articles about the British Lucanidae.

Links to 'ARKive' species accounts: